Issue:
Diagnostic: 1A5 or 1A6 Oil Flow Control
Resolution:
RTAA 130-400 TON chiller.
This diagnostic is generated at the time compressor shuts down. The compressor will not restart.
- When the chiller control sends a signal to stop the compressor a 20 second Run: Unload timer starts. (Shutdown Test)
Next the UCM will de-energize the oil line solenoid and set a 10 +/- 1 second timer.
Usually the differential pressure switch will open in (0.8 - 1.2 sec.) and the compressor will be de-energized and the sequence ended.
- If the differential pressure switch does not open within 10 seconds, the compressor shall be de-energized and the (Oil Flow Control) CMR diagnostic will be generated not permitting the compressor to restart.
- The chiller control will not initiate the (Shutdown Test) whenever the fan control pressure differential is below 70 psid, or if a diagnostic shutdown occurs. The normal Shutdown Test will serve to check the differential pressure switch, the switch wiring to UCM, and closure of the oil line solenoid valve.
Troubleshooting:
- Verify DP Switch calibration...50 psi.
- Verify Master Oil Solenoid Valve is closing/shutting off.
- Verify DP Switch Capillary Tube connection points schrader/depressor are working correctly.
- Insert swivel "T's" on the low and high side of the DP switch and measure differential pressure during operation and shutdown.
Notes:
Changes:
Other Question/Problem/Cause Statements:
- Diagnostic: 1A5 or 1A6 Oil Flow Control
- Oil flow control
Facts:
- Air-Cooled Chiller (Pueblo) (RTAA 130-400 Ton)
Original HUB Document: DOC-76339
WARNING:
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